Printing presses produce quality reproductions on paper webs traveling through the press at high speeds. Care must be taken to maintain the integrity of the web since a break in the rapidly moving web releases the tension exerted on the paper web to pull it through the printing unit. When this occurs, the web jams the printing press causing damage to the fragile print blankets and lengthy down time associated with cleanup, repair, and restringing the paper web through the printing units.
Typically available web break detectors sense the web break, shear the paper web immediately downstream of the printing unit, and shut down the printing unit. However, during the lag time between sensing the break and shut down, the paper web may wrap up on the printing cylinders and damage the print blanket.
Those concerned with these and other problems recognize the need for an improved printing web tensioning system to maintain tension on the web during the shut down process.